CN1792113B - Method for establishing connection in radio communication system, related system and base station - Google Patents

Abstract

The present invention proposes a new downlink MBMS Associated Control Channel (MACCH), combining the functionalities of a broadcast channel and of an associated point-to-multipoint control channel, to be transmitted by a base station (BTS) to a user equipment (UE). By referring to specific information contained in the channel the user equipment (UE), establishes a point-to-point connection with the base station (BTS) without interrupting the reception of a broadcast/multicast service (MBMS).

Description

Method for establishing connection in radio communication system, related system and base station

technical field

The invention relates to a method for establishing a connection in a radio communication system, in particular a mobile radio communication system.

Background technique

In radio communication systems, signals are exchanged between a radio terminal and a radio station to a base station via a so-called radio interface or air interface. These radio terminals are mobile or stationary user terminals (UE-User Equipment); base stations (NB-Node B) are access stations in relation to land-based communication networks. Examples of known radio communication systems are second generation digital mobile radio communication systems like GSM (Global System for Mobile Communications), which are based on TDMA (Time Division Multiple Access) and provide data rates up to 100 kbit/s, or UMTS A third-generation digital mobile radio communication system such as (Universal Mobile Telecommunications System) which is based on CDMA (Code Division Multiple Access) and has a data rate of up to 2 Mbit/s.

A new feature in current radio communication systems such as GSM/GERAN (GSM Edge Radio Access Network) and UMTS/UTRAN (UMTS Terrestrial Radio Access Network) is the so-called MBMS (Multimedia Broadcast/Multicast Service) service offering. If there is a user equipment in a cell in which a special MBMS service has been activated, then a radio bearer for multicast MBMS service is established in this cell. If the number present is below a predetermined threshold, a radio bearer (point-to-point bearer) to each user equipment is established individually, while if the number exceeds the threshold, a single multicast radio bearer is established to serve all users present in the cell equipment. Therefore, the network must know whether the number of user equipments present in the cell exceeds a threshold, and if less than the threshold number occurs, the identity of the user equipments must also be known in order to establish an individual connection. For user equipments in so-called UMTS connected mode, the network is able to determine the number of user equipments present in a cell in which a particular MBMS service has been activated, without having to communicate directly with the user equipments. For a user equipment in a disconnected state, e.g. in a so-called idle mode or URA_PCH (UTRAN Registration Area Paging Channel) state, the network will have to signal a request to the user equipment, e.g. by paging or signaling on a control channel , and the user equipment will have to respond on the common uplink signaling channel RACH (Random Access Channel). The counting of user equipment responses should be completed within a certain time interval, and it is decided to establish or not establish a single multicast radio bearer according to the result of the counting procedure.

A major difference of MBMS from known services is that it can be offered and used when the user equipment is in idle mode, ie when no radio connection is established with the network. This service uses point-to-multipoint connections in multicast mode or broadcast mode. In the standard document 3GPP TR 25.992, V1.2.0 (2003-01) "Multimedia Broadcast Multicast Service (MBMS); UTRAN/GERAN Requirements"; TR23.846, V6.1.0 (2002-12) "MBMS; Architecture and functional description (Release 6)"; TS 22.146, V6.1.0 (2002-09) "MBMS; Stage1 (Release 6)"; TS 45.002, V5.7.0 (2002-11) "Multiplexing and multiple access on the radio path (Release 5)"; TS44.018, V4.12.0 (2002-12), "Radio Resource Control (RRC) protocol (Release 4)"; and TS 44.060, V6.0.0 (2002-12) "General Packet Radio Service (GPRS); Mobile Station ( MS)-Base Station System (BSS) interface; Radio Link Control/Medium Access Control (RLC/MAC) protocol" describes the general principles of MBMS.

Since user equipments are kept in idle mode in order to save radio resources, the radio network does not know the number and location of user equipments currently using point-to-multipoint connections in a given cell. If a user equipment in this state wishes to establish a new point-to-point radio connection with the network to send e.g. user data or Non-Access Stratum (NAS) data, it must Access to the network on such a random channel. In order to access RACH or PRACH, user equipment may have to switch to (P)BCCH ((Physical) Broadcast Control Channel) frequency and continuously read (P)AGCH (Access Grant Channel) to receive its channel assignment. This may lead to long interruptions in reception of MBMS services which may be delivered on another frequency, or which may be incompatible with user equipment capabilities in case MBMS bearers are allocated on the same (P)BCCH frequency .

To alleviate this problem, it has been proposed to use a specific MBMS RACH channel (MRACH) which uses an uplink channel corresponding to a downlink MBMS channel. It is also assumed that resource allocation for ongoing connections will be made on the available (P)AGCH, which carries the same MBMS service interruption risk as above.

Contents of the invention

It is therefore an object of the present invention to provide a method for efficiently establishing a new connection in the above-mentioned situation. This object is solved by the solution according to the invention.

The invention provides a method for establishing a connection between at least one user equipment and a base station in a cellular radio communication system, the method comprising the following steps:

- sending a multimedia broadcast/multicast service carrier having a frame structure from said base station;

- assigning specific information to at least one frame of the MBMS carrier by the base station, wherein the specific information includes a combination of broadcast and related control information, and the specific information includes a method for homing user equipment address identifier;

- receiving said MBMS carrier on said at least one user equipment;

- in response to receiving said specific information in said MBMS carrier, establishing communication from said at least one user equipment to said base station without interrupting reception of said MBMS carrier connect.

Furthermore, the present invention provides a radio communication system comprising:

The base station, the base station further includes:

- sending means, suitable for sending a multimedia broadcast/multicast service carrier having a frame structure;

- assigning means in said base station adapted to assign specific information to at least one frame of said MBMS carrier, wherein said specific information comprises a combination of broadcast and related control information, and said specific information comprises an identifier for addressing user equipment, and

user equipment, the user equipment further comprising:

- receiving means adapted to receive a multimedia broadcast/multicast service carrier using a frame structure;

- establishing means adapted to establish a connection to a base station without interrupting reception of said MBMS carrier in response to said receiving means receiving said specific information in said MBMS carrier .

In addition, the present invention provides a base station, including:

- sending means, suitable for sending a multimedia broadcast/multicast service carrier having a frame structure;

- assigning means adapted to assign specific information to at least one frame of said MBMS carrier, said specific information comprising a combination of broadcast and related control information, and said specific information comprising a method for homing user equipment An identifier of an address, wherein the user equipment can establish a connection without interrupting reception of the multimedia broadcast/multicast service carrier when receiving the specific information.

The present invention builds a new downlink MBMS-related control channel (MACCH) that combines the functions of the broadcast channel and the associated point-to-multipoint control channel, thereby avoiding any interference with the reception of MBMS services by user equipment when an additional connection is being established. interruption. However, the scope of the present invention is not limited to the above examples.

Description of drawings

The invention may be more readily understood, and various other aspects and features of the invention may become apparent, by consideration of the following description and drawings as illustrated in the accompanying drawings, in which:

Figure 1 shows a block diagram of a radio communication network.

Figure 2 shows the format of MBMS neighbor cell channel information.

Figure 3 shows a basic diagram of a base station (BTS) and user equipment (UE).

Detailed ways

Figure 1 shows the basic structure of the GSM mobile radio system. The system includes a central mobile switching center MSC connected to the public switched telephone network PSTN and other MSCs. A plurality of base station controllers BSC are connected to the MSC, wherein the plurality of base station controllers BSC coordinate inter alia the sharing of the provided radio resources by the base stations BTS (Base Transceiver Station). The base station BTS transmits signals on the downlink DL to the user equipment UE located in the coverage area of the base station BTS or receives signals on the uplink UL from the user equipment UE located in the coverage area of the base station BTS. In Fig. 1, the base station BTS sends a request for activating the MBMS multicast service to the user equipments in its cell on the paging channel PCH. User equipments interested in this service or having special characteristics respond to this request by sending access messages on the contention-based access channel RACH. In Fig. 3, the base station (BTS) includes sending means (10) and allocating means (20), while the user equipment (UE) includes receiving means (30) and establishing means (40).

According to the invention, the so-called MACCH fulfills the function of the (P)AGCH and the downlink aspect of the PACCH (Packet Associated Control Channel, see TS 45.002). This can be achieved because on the one hand the MACCH provides several or all of the messages available on the PACCH and (P)AGCH, ie messages for channel grants and messages for control purposes. Additional information may be defined for specific purposes of MACCH. On the other hand, MACCH is identified by PACCH (ie, slot, frequency and/or Transport Format Indicator (TFI)). If the MACCH is used as a point-to-point channel, the message can include an identifier in order to address a particular user equipment, so as known from the MRACH random reference or TLLI (Temporary Logical Link Identifier) can be achieved The identity of the user's device. TLLI provides a signaling address for communication between UEs and network nodes that tracks the location of individual UEs. If the MACCH is used as a point-to-multipoint channel, the user equipment can be addressed using a global user equipment identifier, eg a default null identifier. In both cases, the User Equipment (UE) receiving means (30) are adapted to identify that the identifier has been received, and the receiving means (30) are also adapted to identify between received broadcast and/or control information.

Another feature, if the MACCH is used as a point-to-multipoint channel, is that the message may include information on frequencies allocated to MBMS traffic channels and notification channels in neighboring cells. This will speed up the cell reselection procedure in case the UE changes cells, since the UE can start receiving MBMS data while still reading the system information in the new cell. The time of service interruption due to UE moving from one cell to another is thus shortened. This message is sent on the MACCH and is called "MBMS Neighbor Cell Channel Information". One possible format of this message is shown in FIG. 2 .

The parameter "Ce11 ID" indicates which cell the Frequency Parameter Information Element IE relates to. This parameter is an index into a neighbor cell list. The length of the field depends on which list is used to identify the cell. For example, if it is a GSM neighbor cell list, 6 bits are required, because defined in TS44.060, 6 bits are the length of the Frequency_N parameter in the packet measurement report message or the removed_freq_index in the packet measurement sequence message. If using 3G Neighbor Cell List, 7 bits are required.

When establishing MBMS communication, a hopping channel is used between the UE and the base station. As is known in the art, three different methods for encoding the frequency parameters defining a radio frequency hopping channel are used: indirect encoding, direct encoding 1 and direct encoding 2, where the frequency parameter in the assignment message sent to the UE.

In indirect coding, the allocated set of radio frequency channels is defined by reference to information stored within the UE; such information may be received on the PBCCH or BCCH, or in a previous allocation message. In direct coding, the allocated set of radio frequency channels is defined by using information contained in the allocation information itself. Direct Coding 1 decodes this information with reference to the cell assignment or Reference Frequency List (RFL) received on the PBCCH. Direct Encoding 2 is independent. A frequency list is a representation of a set of radio frequency channels defining a general packet radio service (GPRS) mobile allocation. The encoding of octet strings is defined in TS 44.018, and the permissible format for such information is defined in TS 44.060. In addition, the UE can store up to 12 to 16 sets of frequency parameters for each neighboring cell. The provided cell frequency parameters are those that have a high probability of being selected by UEs listening to the MBMS service. As can be seen in Figure 2, the message is coded in such a way as to provide an MBMS channel description of only one neighboring cell, however, as will be known to those skilled in the art, the message can be modified to include frequency information for more cells, Or alternatively send a series of messages containing frequency information for each cell.

As in the case of PACCH, the resource allocation of MACCH is realized by stealing the frame of MBMS channel, so the use of MACCH should be minimized. Therefore, user equipments that have established point-to-point and point-to-multipoint connections should rather use PACCH than MACCH.

The advantage of this method according to the invention is that parallel point-to-point connections are established without interrupting the reception of point-to-multipoint MBMS services.

Any operation on the point-to-point bearer can be performed just like the operation on the point-to-point bearer in the case of PACCH.

Incorporating MRACH will optimize these advantages, however the functionality of MRACH is not a prerequisite for MACCH.

The invention resides in the combination of a broadcast common channel and a point-to-point related control channel and the fact that, in order to allow optimal use of scarce radio resources, the user equipment notifies the point-to-multipoint bearer established during the early access phase to network. In the nomenclature of UTRAN (UMTS Terrestrial Radio Access Network), MACCH can be defined as a transport channel on which (P)AGCH, point-to-multipoint PACCH and point-to-point PACCH are mapped.

Claims (14)

1. one kind is used for the method that connects at celluler radio communication system between at least one subscriber equipment (UE) and base station (BTS), and this method may further comprise the steps:

-send multimedia broadcast/group broadcast service carrier wave with frame structure from described base station (BTS);

-distribute customizing messages by described base station (BTS) at least one frame of described multimedia broadcast/group broadcast service carrier wave, wherein said customizing messages comprises broadcasting and the combination of related control information mutually, and described customizing messages comprises the identifier that is used for subscriber equipment is carried out addressing;

-go up the described multimedia broadcast/group broadcast service carrier wave of reception at described at least one subscriber equipment (UE);

-in response to the described customizing messages that receives in the described multimedia broadcast/group broadcast service carrier wave, under the situation of the reception of not interrupting described multimedia broadcast/group broadcast service carrier wave, set up connection from described at least one subscriber equipment (UE) to described base station (BTS).

2. according to the process of claim 1 wherein that described connection can be the point-to-point connection or put the multiple spot connection.

3. according to the process of claim 1 wherein that at least one frame to described multimedia broadcast/group broadcast service carrier wave distributes the step of customizing messages also to comprise from described broadcasting/packet service carrier wave and diverts at least one frame and described customizing messages is assigned to step its position.

4. according to the method for claim 2, wherein when using described customizing messages to set up a little to the multiple spot connection, described customizing messages comprises adjacent cell information.

5. according to the method for claim 4, wherein said adjacent cell information comprises frequency parameter.

6. according to the method for one of aforesaid right requirement, comprise the step that described customizing messages is encoded.

7. radio communications system comprises:

Base station (BTS), this base station further comprises:

-dispensing device (10) is suitable for sending the multimedia broadcast/group broadcast service carrier wave with frame structure;

Distributor (20) in-described base station (BTS), be suitable for distributing customizing messages at least one frame of described multimedia broadcast/group broadcast service carrier wave, wherein said customizing messages comprises broadcasting and the combination of related control information mutually, and described customizing messages comprises the identifier that is used for subscriber equipment is carried out addressing, and

Subscriber equipment (UE), this subscriber equipment further comprises:

-receiving system (30) is suitable for receiving the multimedia broadcast/group broadcast service carrier wave that uses frame structure;

-apparatus for establishing (40) is suitable for responding that described receiving system receives the described customizing messages in the described multimedia broadcast/group broadcast service carrier wave and the connection that is established to base station (BTS) under the situation of the reception of not interrupting described multimedia broadcast/group broadcast service carrier wave.

8. according to the system of claim 7, wherein in described subscriber equipment (UE), described apparatus for establishing (40) is suitable for setting up point-to-point or puts multiple spot and connects.

9. according to the system of claim 7, wherein in described subscriber equipment (UE), described receiving system (30) also is suitable for discerning between broadcasting and/or control information.

10. according to the system of claim 8, wherein when using described system to set up described point-to-point to connect, described base station (BTS) distributor (20) also is suitable for branch and is used in the identifier that special user's equipment is carried out addressing, and described subscriber equipment (UE) receiving system (30) also is suitable for discerning described identifier.

11. system according to claim 8, wherein when using described system to set up described point when multiple spot connects, described base station (BTS) distributor (20) also is suitable for distributing global user equipment identifiers and/or adjacent cell frequencies parameter, and described subscriber equipment (UE) receiving system (30) also is suitable for discerning described global user equipment identifiers and/or described adjacent cell frequencies parameter.

12. according to the system of claim 7, wherein said base station (BTS) distributor (20) also is suitable for diverting at least one frame and described customizing messages being assigned to its position from described broadcasting/packet service MBMS carrier wave.

13. a base station (BTS) comprising:

-dispensing device (10) is suitable for sending the multimedia broadcast/group broadcast service carrier wave with frame structure;

-distributor (20), be suitable for distributing customizing messages at least one frame of described multimedia broadcast/group broadcast service carrier wave, described customizing messages comprises broadcasting and the combination of related control information mutually, and described customizing messages comprises the identifier that is used for subscriber equipment is carried out addressing

Wherein subscriber equipment (UE) can connect under the situation of the reception of not interrupting described multimedia broadcast/group broadcast service carrier wave when receiving described customizing messages.

14. according to the base station (BTS) of claim 13, wherein said distributor (20) also is suitable for diverting at least one frame and described customizing messages being assigned to its position from described broadcasting/packet service carrier wave.

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